Letter from the 5th Earl of Cranbrook to Edward Dickinson on various species and subspecies of Collocalia

Letter from the 5th Earl of Cranbrook to Geoffrey Allen on the swiftlet gigas not being a Collocalia and that gigas do not echolocate

Letter from the 5th Earl of Cranbrook to George Smith on the display pattern made by a spectograph. He said the equipment used was a "sona-analyser" and was set up to respond to 12Kc/sec

Letter from the 5th Earl of Cranbrook to H. M. Burkill, thanking him for the identification. The Earl said he would send Burkill the information on the determinations

Letter from the 5th Earl of Cranbrook to Humayun Abdulali on nests of swiftlets

Letter from the 5th Earl of Cranbrook to Humayun Abdulali on the swiftlets found in the cave in Car Nicobar. He mentioned Tom Harrisson was killed in a traffic accident in Bangkok and that he had a paper on swiftlet diets in press

Letter from the 5th Earl of Cranbrook to J. R. David Wall informing him swiftlets usually made their nests inside rather than outside the caves

Letter from the 5th Earl of Cranbrook to Jacob Lawai Nawan with advice on their mutual concern about the natural habitat in part of Baram being damaged

Letter from the 5th Earl of Cranbrook to Jajasan Siswa Lokantara on the Earl's final report of his main achievements of his work in Indonesia while holding a studentship from Jajasan Siswa Lokantara

Letter from the 5th Earl of Cranbrook to Joe T. Marshall on location of Selidang. He also mentioned tapes of swiftlets' calls